1. Field of the Invention
The present invention relates to a seat belt for protecting a vehicle occupant during a vehicle collision and, more particularly, to an inflatable belt which is capable of being inflated with gas.
2. Description of the Related Art
An inflatable belt device of this type is disclosed in Japanese Unexamined Patent Publication H05-85301 and is shown in FIGS. 6(a) and 6(b). This passenger protective device 1 includes a shoulder belt 2 extending diagonally from the right side to the left side of a passenger, a lap belt 3 extending from the right side to the left side of the passenger, a buckle 4 fixed to, for example, a vehicle floor, a tongue 5 to be inserted into and engaged with the buckle 4 when the passenger wears the belt, and an intermediate guide 6 for guiding the shoulder belt 2.
The shoulder belt 2 includes a normal webbing 2a, which is the same as a typical conventional seat belt, and an inflatable belt 2b connected to an end of the webbing 2a. The webbing 2a is slidably hung in the intermediate guide 6. The other end of the webbing 2a is connected to a shoulder belt retractor 7 with an emergency locking mechanism (ELR), which is fixed to the vehicle body. The webbing 2a is arranged such that it is wound into the shoulder belt retractor 7.
The inflatable belt 2b is positioned so that it contacts the passenger and is connected to the tongue 5 at an end opposite to the end connected to the webbing 2a. The lap belt 3 is composed of a normal webbing, which is the same as a typical conventional seat belt, having one end is connected to the tongue 5 and the other end connected to a lap belt retractor 8 (ELR), which is fixed to the vehicle body. A gas generator 9 is connected to the buckle 4. The gas generator 9 is actuated in emergency situations, e.g., vehicle collisions, to generate high-pressure gas. The tongue 5 and the buckle 4 are each provided with passages for introducing gas from the gas generator 9 into the inflatable belt 2b.
The inflatable belt 2b of the shoulder belt 2 includes a belt body 2c formed in an envelope-like shape and a cover 2d. The belt body 2c is folded, shown in solid lines in FIG. 6(b), and then covered by the cover 2d. The ends of the cover 2d are then connected to each other by stitching 2e so that the inflatable belt 2b is maintained in a band-like configuration. The stitching 2e of the cover 2d is easily torn by the force of the shoulder belt 2 expanding when the gas generator 9 is actuated so that the inflatable belt 2b is deployed, shown by a two-dot chain line in FIG. 6(b).
The belt body 2c is made of, for example, rubber coated fabric and the cover 2d is made of a flexible knit with excellent stretchability.
The conventional inflatable belt feels very stiff when touched by a vehicle occupant.